Half awake makes half asleep: monocular deprivation in chicks (Gallus gallus)

Abstract

Event Abstract Back to Event Half awake makes half asleep: monocular deprivation in chicks (Gallus gallus) Daniela Bobbo1*, Angelica Quercia1, Cristian Nelini1 and Gian Gastone-Mascetti1 1 University of Padova, Italy Chicks exhibit unihemispheric sleep, in which one hemisphere is awake while the other is sleeping. Previous studies suggested that unihemispheric sleep in chicks is associated with the lateralization of brain functions. Many functions of the young chick’s brain are lateralized and these correlate with asymmetry in the organization of visual projections. Monocular deprivation (MD) in the sensitive period of the development of the visual system can influence pre-hatch asymmetries [1]. Sleep behaviour (eye closure) was investigated in 48 female chicks of 2 days post-hatching. MD was performed by placing an eye-patch for a duration of 12 hours. 24 animals came from eggs dark-incubated eggs and 24 animals came from light-incubated eggs. The right eye was occluded in a group of chicks (n=8, L-RE; n= 8, D-RE), the left eye was occluded in a second group (n=8, L-RE; n=8, D-LE) whilst a third group was maintained with both eyes uncovered (n=8, L-CONTROL; n=8, D-CONTROL). Sleep behaviour was recorded for 6 consecutive hours, immediately after the end of MD. In general, MD exclusively affected unihemispheric sleep: LE-chicks (both light and dark-incubated) showed a strong preference for right eye closure, whereas only RE-chicks came from dark-incubated eggs showed a preference for left eye closure. In order to investigate the possible effects of MD on the imprinting process, we also recorded the locomotor activity and spatial positions during and after MD in 18 female chicks at 2 days post-hatching (n = 3, Light-RE; n = 3, Dark-RE; n = 3, Light-LE; n = 3, Dark-LE; n = 3, Light-CONTROL; n = 3, Dark-CONTROL).